Short-acting β-agonist use as a marker of current asthma control

Background The relationship between current asthma symptoms and rescue bronchodilator (reliever) use is uncertain, leading to different recommendations about the preferred reliever metric to use when assessing asthma control. In a 6-month randomized controlled trial of combination budesonide/formoterol as maintenance and reliever therapy versus combination budesonide/formoterol as maintenance treatment with albuterol as reliever, we measured inhaler use by electronic monitoring. Objective To determine the agreement between current asthma symptoms and different metrics of albuterol use for patients randomly assigned to maintenance budesonide/formoterol treatment. Methods Data on albuterol use were extracted for the 7-day period before visit 2 (at week 3) from 150 adult patients with asthma. Current asthma symptoms were measured by Asthma Control Questionnaire-5 (ACQ-5) score at the clinic visit. Results The number of days of albuterol use, the average number of albuterol actuations/day, and the highest number of albuterol actuations/day in the 1-week period were all positively associated with ACQ-5 score (r = 0.41-0.45, P < .001) and had moderate discrimination for well-controlled and not well-controlled asthma (ACQ-5 scores ≤0.75 and ≥1.5, respectively), with receiver operator characteristic area under the curve of 0.80 to 0.82 and 0.70 to 0.77, respectively. Cut points of ≥3 days of albuterol use, average albuterol use of ≥1 actuation/day, and highest albuterol use of ≥4 actuations/day in the 1-week period had 73% sensitivity and 62% specificity, 78% sensitivity and 67% specificity, and 78% sensitivity and 66% specificity, respectively, for predicting an ACQ-5 ≥1.5. Conclusion Our findings support the use of the number of days of albuterol use, the average number of albuterol actuations per day, and the highest number of albuterol actuations per day over a 1-week period of observation as comparable markers of current asthma control